Study on deformation mechanism and control technology of rock pillar in near-vertical coal seams mining

To address the frequent appearance of dynamic disasters during the mining of near-vertical coal seams (NVCS), this study takes the Wudong Coal Mine as the research object and employs methods including theoretical analysis, numerical simulation, and engineering verification. It investigates the mechanism of dynamic disasters induced by the prying deformation of rock pillar, analyzes the stress and energy evolution patterns within the rock pillar, and optimizes the pressure relief blasting scheme. The results indicate that the prying-induced extrusion of interlayer rock pillar serves as the primary source of dynamic loading. A stress concentration zone, measuring 54 m in height and 22 m in width from the B2 roadway, was identified, with stress levels exceeding 21 MPa. This zone is concentrated within 20 m before and after the working face as it advances. Energy accumulation within the rock pillar primarily occurs in the goaf left by the previous mining stage, aligning with the prying extrusion location identified in the theoretical analysis. Based on these findings, ANSYS numerical simulation software was used to optimize blasting parameters, including the blasting method, borehole diameter, and borehole layout. The resulting scheme consists of three deep holes (reverse initiation) and two shallow holes (forward initiation). Field application demonstrates that this optimized blasting scheme effectively reduces high-energy and high-pulse mining microseismic events, achieving a notable pressure relief effect. These findings offer a significant reference point for the management of dynamic disasters in similar mining environments.